Juxtaposing Martin Buber and Emmanuel Levinas is irresistible. Both are solidly rooted in Judaism. Both are philosophers who have broken with the central thrust of philosophy from Plato to Heidegger in favor of a radical relation to otherness, alterity. Both are centrally concerned with ethics. Both link the relationship with God with the relationship with our fellow human beings. Both are thinkers who lived, wrote, and acted in the present century.
Beyond that, important differences begin to emerge. Although Buber was as much of a Maskil (a person concerned with enlightenment) as he is a Hasid, he was open to mysticism and myth in their many forms and espoused a teaching of Hasidism and Judaism that might be called a concrete mysticism of hallowing the everyday. Levinas, in contrast, was a mitnagid, the traditional opponent of the Hasidim. He rejected both mysticism and myth as pagan and polytheistic. He was rooted in the Bible, as he saw it, with the emphasis on its moral injunctions and its laws, and in the Talmud. Buber was rooted in the Hebrew Bible as a covenant between a people and God to make real the kingship of God in history by establishing communities and societies of righteousness, justice, and lovingkindness.
From this we turn to the differences in their philosophies. Levinas was a philosopher's philosopher. He constructed a full-scale philosophy and, despite his turning away from both Husserl and Heidegger, many aspects of a phenomenology. At the core of Buber's thought, in contrast, were philosophical insights that he elaborated and illustrated with philosophical consistency. Yet Buber did not construct a systematic philosophy, much less a phenomenology. As Andrew Tallon has put it, Buber initiated a revolution in philosophy in the twentieth century but he did not carry through. In his last commentary on Buber, Levinas wrote:
That valuation of the dia-logical relation and its phenomenological irreducibility, its fitness to constitute a meaningful order that is autonomous and as legitimate as the traditional and privileged subject-object correlation in the operation of knowledge-that will remain the unforgettable contribution of Martin Buber's philosophical labors.... Nothing could limit the homage due him. Any reflection on the alterity of the other in his or her irreducibility to the objectivity of objects and the beings of beings must recognize the new perspective Buber opened-and find encouragement in it.1
Once after I gave a paper on Franz Rosenzweig's critique of Buber's Ich and Du at the annual conference of the American Academy of Religion, a distinguished scholar of the history of religion asked me why it was that people now seemed to have turned from Buber to Rosenzweig. My own response to this question is that Rosenzweig offers us a systematic philosophy whereas Buber does not. The same, I believe, explains in part the recent popularity of Levinas in comparison to Buber, especially among philosophers. If I am right, then it is worth our while to look at what Buber himself said about this in the "Philosophical Accounting" section of his "Replies to My Critics" in The Philosophy of Martin Buber volume of The Library of Living Philosophers.
Since I matured to a life from my own experience ... I have stood under the duty to insert the framework of the decisive experiences that I had ... into the human inheritance of thought, but not as "my" experiences, rather as an insight valid and important for others and even for other kinds of men. Since, however, I have received no message which might be passed on in such a manner, but have only had the experiences and attained the insights, my communication had to be a philosophical one. It had to relate the unique and particular to the "general," to what is discoverable by every man in his own existence. It had to express what is by its nature incomprehensible in concepts that could be used and communicated (even if at times with difficulties). …